1. Field of the Invention
This invention relates to a connector for truss structure which is suitable for a connection of structural members in a wooden structure, in particular for a connection between the structural members in a truss structure.
2. Description of the Related Art
In recent years, there have been developed various kinds of structural laminated woods so as to apply some features of wood, artificially to improve the structural defects such as knots as found in natural materials and to get a heavy timber, long and large timber which is difficult to get from natural timber material. Along with this trend, it has been required to provide a connector for truss corresponding to a truss connection in the wooden structure.
The prior art connector for truss will be described as follows.
In the prior art, the connector for truss corresponding to the truss of the wooden structure has been used in such a manner that a bolt and nut are used for connecting the structural members to each other.
For example, 1 the gazette of Japanese Patent Laid-Open No. Hei 4-41831 discloses a light-weight dome and a connector for the dome in which a pair of metallic connectors are welded in a radial spaced-apart relation to an outer circumference of a tube-like boss member, a wooden supporting member is held by a pair of metallic connectors and fastened and fixed with the bolts and nuts, and 2 the gazette of Japanese U.M. Laid-Open No. Hei 4-13703 discloses a connector for connecting the wooden truss members by a method wherein an end surface of the wooden member is punched with a bolt embedding hole, a bolt is embedded into the bolt embedding hole, the bolt is integrally fixed to the wooden member with the adhesive agent and the bolt is fastened to a connector fitting with nut.
However, in the aforesaid prior art configuration, in particular 1 had some problems that many parts such as bolts, nuts and washers were required for connecting the structural members, fixing work for the structural members was troublesome and its workability was lacked. In addition, the prior art had other problems that the fitting was large in size, its transporting characteristic was not satisfactory, and in particular its working at a high-elevated location was lack of safety.
Additionally, the prior art structure in which the wooden supporting members were fastened and fixed with bolts and nuts had some problems that its fastening force is lost in several years due to shrinkage of the wooden material to cause a certain looseness to be easily generated there and its physical strength was reduced.
Additionally, in 2 it had some problems that it was necessary to insert and fix the bolts in the wooden member by adhesive agent in advance and in the case that the members were damaged during installing work or erroneous size occurred in the members, its accommodation for these accidents is difficult at site and its installing workability is not satisfactory. In addition, the prior art had other problems that confirmation whether or not adhesive agent for use in fixing the bolts is uniformly filled in the bolt embedding hole in the wooden member, positively adhered to and fixed to it can not be performed and this shows a certain problem in quality control. Further, the prior art had another problem that if the nut is too fastened when this wooden member is to be fixed to the connector, the adhesive agent adhering and fixing the bolt to the wooden member was easily damaged due to a pulling force of the bolt, and its safety in operation was not satisfactory.